To the Editor:
Infusions of crystalloid solutions are currently recommended for the treatment of critically ill patients with various pathologic conditions, including bleeding, sepsis, and trauma.1–3 A large number of prospective randomized multicenter studies on the comparative analysis of 0.9% sodium chloride and balanced crystalloid have examined their efficacy and safety. However, the answer to the question of whether the crystalloid composition affects the treatment outcome in critically ill patients has not yet been received.1 It should be noted that currently, when assessing the pharmacodynamic effects of crystalloid solutions, their actual physicochemical parameters, such as osmolality and pH, are not taken into account. Researchers prefer to use theoretically calculated parameters, and in our opinion, this reduces the accuracy of the results. The fact is that the theoretical osmolarity values of solutions can differ significantly from their actual osmolality values. We suggested that the same crystalloid solutions provided by different manufacturers may have different values of both osmolality and pH. To prove that, we studied physicochemical parameters (osmolality and pH) of 0.9% sodium chloride by different manufacturers. We chose 0.9% sodium chloride because this crystalloid solution is used as a reference in all randomized controlled studies on the pharmacodynamics of crystalloid solutions. The analysis of 0.9% sodium chloride osmolality was carried out with the help of vapor pressure osmometer model 5600 (Wescor Inc., USA). The actual pH of each solution was determined using the product specification sheet of 0.9% sodium chloride of a certain series. The analysis of the studied physicochemical parameters of certain series of 0.9% sodium chloride by eight different manufacturers revealed that the osmolality value range was from 278 mmol/kg (270319 series, Biosintez, Russia) to 305 mmol/kg (160115 series, Zavod Medsintez, Russia), and the pH value range was from 5.4 (14791119 series, Grotex, Russia) to 6.3 (B7571218 series, Pharmasyntez Tyumen, Russia). The results obtained indicate that 0.9% sodium chloride by different manufacturers has different physicochemical properties. Considering the fact that during the treatment of critically ill patients 0.9% sodium chloride can be introduced into the patient’s body in large volumes, the osmolality and pH of the solution may have a great impact on the pharmacodynamic effect. Determining the actual values of the physicochemical parameters of 0.9% sodium chloride and balanced crystalloid can increase the accuracy of the results of randomized multicenter studies in the future.
The authors declare no competing interests.